1. Field of the Invention
The invention relates essentially to a process for manufacturing von Willebrand factor having a very high purity, and to the von Willebrand factor thereby obtained as well as to a pharnaceutical composition containing it.
2. Description of the Related Art
Various processes for manufacturing von Willebrand factor are already known in the prior art. These processes are, in general, mainly directed towards obtaining factor VIIIc of high purity, the von Willebrand factor being obtained as a byproduct. For example, the document EP-A-0,359,593 (CRTS Lille) describes a process for separating proteins from a fraction of human or animal plasma, according to which a factor VIIIc concentrate of high purity which is usable for the treatment of haemophilia A is obtained, as well as concentrates of fibrinogen, of von Willebrand factor and of fibronectin. According to this previous process, the factor VIIIc obtained is only partially freed from von Willebrand factor, and this constitutes a drawback of this process.
In the document FR 89/02,136 of the Applicant, a process has been described for manufacturing antihaemophilic factor (FVIIIc) having a very high purity, making it possible to obtain, as secondary constituents, von Willebrand factor, the method of purification of which was not described.